Ski tube



FIG. 1 is a perspective view of a ski tube showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof, the opposite side being a mirror image;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a a front elevation cross-sectional view thereof. 

The ornamental design for a ski tube, as shown and described. 